// concat 连接buffer

let buf2 = Buffer.from('珠')
let buf3 = Buffer.from('峰')
let res = Buffer.concat([buf2, buf3])
Buffer.concat = function(list, total=list.reduce((len,item)=>len+item.length,0)){
    if(list.length == 1){
        return list[0]
    }
    let res = Buffer.alloc(total)
    let index = 0
    for(let buf of list){
        for(let b of buf){
            res[index++] = b
        }
    }
    return res
}
console.log(res.length)